class AST::FunctionDefinition
  attr_reader :name, :parameters, :body, :env

  def initialize(name, parameters, body, env = nil)
    @name = name
    @parameters = parameters
    @body = body
    @env = env
  end

  def ==(other)
    other.is_a?(AST::FunctionDefinition) && other.name == @name &&
      other.parameters == @parameters &&
      other.body == @body
  end

  def execute(env)
    return AST::FunctionDefinition.new(@name, @parameters, @body, env) if @name.nil?
    env.set(@name.name, self)
  end
end